This invention relates generally to devices and methods for monitoring and regulating the water chemistry in a spa or hot tub or the like, to maintain the water quality at a clean, clear, and substantially sanitary condition. More specifically, this invention relates to a self-contained and free floating monitor unit for checking selected water chemistry parameters at programmable intervals, and for automatically responding to the monitored parameters by delivering one or more chemical additives to the water to maintain the spa water in a clean and hygienic state.
Therapeutic spas and hot tubs and the like are generally known in the art, and typically comprise an upwardly open structure adapted to contain a selected volume of water. Control means are normally provided for heating the water, and for circulating the water through air-water hydrotherapeutic massage jets. One or more persons can sit within the spa, partially immersed within the heated water, in positions so that the spa jets can be directed against the body to provide a therapeutic massage action. To maintain the spa water in a clean and sanitary condition, the circulating water is normally passed through a filter which removes and collects particulate matter. In addition, selected chemical agents, such as chlorine are periodically added to the spa water in prescribed amounts suitable for preventing growth of bacterial organisms, to maintain the water in a hygienic state. Other chemical agents such as a sanitizer, e.g., an oxidizer such as bromine, are also periodically added to the water.
In the past, periodic manual testing of the spa water has been required to determine the actual concentration of chemical agents therein, in order to determine whether one or more chemical agents should be added to the spa water to maintain a desired sanitary condition. In this regard, the pH level (a logarithmic function of hydrogen ion concentration) is commonly checked by the spa owner or by maintenance personnel at regular intervals, and chemical agents such as a selected base or acid are added to the water in appropriate amounts for respectively adjusting the pH level up or down as may be required to maintain the pH reading within a typical desired range of about 7.2-7.8. In addition, oxidation reduction potential (ORP) is also checked regularly, and a selected chemical sanitizer such as bromine is added to the water in an appropriate amount to maintain the ORP reading within a typical desired range of about 650-750 millivolts when the pH reading is within the above-stated desired range. Regular monitoring of the water chemistry, and regular addition of these chemical agents in the appropriate amounts, is essential to maintain the spa water in a clean and sanitary condition. However, manually conducted water chemistry testing and manual addition of the chemical agents has been highly subject to time interval variations and measurement inconsistencies which can have an adverse impact upon water quality.
For some swimming pool and spa installations, devices and systems have been developed for unattended delivery of certain chemical agents to the water over an extended period of time. For example, floating dispensers have been widely used in swimming pool and spa applications, wherein a quantity of a chemical such as chlorine or bromine is carried by a buoyant housing which has a variably opened gate for controlled release of the chemical on a substantially continuous basis and for an extended period of time. In such dispensers, the floating housing typically carries a supply of chemical-containing tablets in solid form, designed for rate-controlled dissolution according to the degree to which the gate is opened. While such dispensers beneficially maintain the chemical concentration, the delivery rate is still predicated upon periodic manual water chemistry testing and corresponding periodic gate adjustment to regulate the chemical delivery rate. Moreover, such floating dispensers have not been designed to accommodate delivery of other chemical agents, such as acids or the like when a reduction in pH level is indicated, or a sanitizer or oxidizer for regulating and maintaining the ORP level within a prescribed reading range. The need for and the addition of such other chemical agents has still relied upon periodic manual water chemistry testing and periodic manual addition of the chemical agents in selected amounts to the pool or spa water.
In other swimming pool and spa installations, substantially automated systems have been designed for integration in-line into the water filtration and circulation equipment for automatically analyzing the water chemistry at periodic intervals, and for responding to the chemistry readings to automatically add chemical agents to the water in prescribed amounts. See, for example, the automated pool water chemistry marketed by Polaris Pool Systems of San Marcos, Calif. under the product designation Watermatic. See also U.S. Pat. No. 5,019,250. Such automated systems, however, are relatively complex and are thus relatively costly, particularly with respect to the requisite plumbing modifications for installation into the filtration system of a preexisting pool or spa. Moreover, the complexity and resultant cost of such automated in-line chemical dispensers has been a significant deterrent to use thereof in stand-alone spas which do not share a water filtration system with an associated swimming pool. Accordingly, such automated chemical dispenser systems have not been widely used.
The present invention overcomes these problems and disadvantages by providing a compact and self-contained floater device for automatically analyzing spa water chemistry at regular programmable intervals, and for automatically responding to the water chemistry readings to add one or more chemical agents in appropriate amounts to maintain the spa water in clean and highly sanitary state.
In accordance with the invention, a water chemistry monitor unit is provided for automated monitoring and regulation of the water chemistry in a spa tub or hot tub or the like, to maintain the water in a clean and sanitary condition. The monitor unit comprises a relatively compact buoyant housing adapted to float freely within the spa water. The monitor unit includes a programmable controller coupled to one or more sensor electrodes for monitoring selected water chemistry parameters at timed intervals. The monitor unit responds to the parameter readings to deliver one or more chemical agents in appropriate amounts to maintain the monitored parameters within prescribed ranges consistent with maintaining the water in a clean and sanitary condition.
In the preferred form, the controller is mounted on-board within the housing of the monitor unit, and an exposed data entry panel is provided for programming the controller to activate the sensor electrodes at predetermined clock times to take readings of the water chemistry parameters. In the preferred form, the sensor electrodes are designed for reading the hydrogen ion concentration level (pH), and for reading oxidation reduction potential (ORP). The controller responds to the pH level reading to deliver an appropriate amount of a selected chemical agent such as a selected base, e.g., sodium carbonate to raise the pH level, or alternately to deliver an appropriate amount of a selected chemical agent such as muriatic acid or other selected acid solution to lower the pH level, for the purpose of maintaining the pH level of the spa water within a predetermined range typically on the order of about 7.2-7.8. In addition, the controller responds to the ORP reading to deliver a selected chemical agent such as a sanitizer or oxidizer, e.g., bromine, to maintain the ORP level of the spa water within a predetermined range typically on the order of about 650-750 millivolts when the pH level is within the above-stated prescribed range.
The chemical agents are carried by the housing of the monitor unit and appropriate amounts thereof are delivered automatically under regulation by the controller, in response to the monitored parameter readings. More particularly, in the preferred form, separate chemical agents such as a base and an acid in liquid form for respectively adjusting the pH level up or down are contained within individual and preferably pre-packaged containers or bottles adapted for mounting in an inverted position within individual and uniquely matingly shaped sockets formed in the unit housing. In the preferred form, an additional or third chemical agent in liquid form such as a strong oxidizer or shock agent or the like, typically a strong chlorine solution, may also be provided within an individual bottle for inverted mounted into a matingly shaped socket on the unit housing. These bottles each include a metering assembly mounted in the neck thereof for engaging an associated plunger of a solenoid actuator mounted on the housing of the monitor unit. In operation, in programmed response to the water chemistry readings, the controller actuates one or more of the solenoid actuators to displace the associated plungers through a selected number of advance and retract strokes, to deliver an appropriate number of discrete doses of the appropriate chemical agent or agents to the spa water.
In addition, in accordance with the preferred form, the chemical agent for regulating ORP level is provided in solid form such as soluble tablets or the like contained within a cartridge suspended from the housing of the monitor unit. The cartridge includes a perforated segment positioned in underlying relation to a rotary gate of perforated construction, wherein the rotary gate is movably positioned by the one or more solenoid actuators in accordance with the detected ORP level to permit or prevent spa water circulation into contact with the soluble tablets in the cartridge. In this manner the perforated segment on the cartridge can be opened or closed to control tablet dissolution and thereby regulate delivery of the associated chemical agent to the spa water. Alternately, the solenoid actuator may be movably positioned for variably opening and closing the perforated segment on the cartridge to variably adjust the rate of chemical addition in response to the ORP reading.
Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.